Chelating polymeric membranes

a polymer membrane and polymer technology, applied in membranes, membrane technology, separation processes, etc., can solve the problems of large amount of organic solvents, and/or irreversible adsorption of metals,

Active Publication Date: 2019-10-22
KING ABDULLAH UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These current recovery and recycling technologies present various disadvantages such as slow kinetics, low selectivity, the requirement of large amounts of organic solvents, and / or irreversible adsorption of metal.
For example, the main disadvantages of solvent extraction methods include the large amounts of organic solvents required, the loss of residual organic solvent to the aqueous phase, and the difficulty of implementing into a continuous process.
However, these extractants exhibit relatively low selectivity, and the subsequent recovery is usually done by reduction of the organic to form metallic gold.
Other drawbacks of ion-exchange resins include the necessity to oxidize the solution before contacting it with the resin, the low capacities of the resins, and the need to operate at slow fluxes to achieve good adsorption.
However, known solid adsorbents for gold recovery present either slow kinetics of adsorption, low capacity, or difficult elution of the gold.
The disadvantage of using activated carbon as the adsorbent is the complexity and cost of the regeneration process.
During this process, a significant amount of carbon can be lost.
Several gold adsorbents can be found in the literature with high maximum uptakes but slow kinetics, as most of them take several hours to reach equilibrium.

Method used

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Examples

Experimental program
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Effect test

example 1

Polythiosemicarbazide (PTSC) Synthesis

[0063]Instructions for synthesizing the PTSC shown in Formula III can be found in Campbell and Tomic, “Polythiosemicarbazides 1. Preparation and Properties of Polymers and Some Simple Metallic Chelates,” J. Polymer Science, 62(174): 379-386 (1962), which is hereby incorporated by reference in its entirety.

[0064]For example, the PTSC shown in Formula III was made by stirring a solution containing 3.1 wt % 1,4-diaminopiperazine, 7.6 wt % of 4,4-methylenebis (phenyl isothiocyanate) and 89.2 wt % of DMSO at 50° C. for 24 hours. The resulting polymer was precipitated in water, chopped into small pieces, washed again with water and dried

example 2

Microporous PTSC Film

[0065]A PTSC polymer was prepared in accordance with Example 1. A polymer solution was prepared comprising 15 wt % PTSC, 75 wt % DMSO, and 10 wt % 1,4-dioxane by mixing the 3 components and stirring for approximately 5 hours at room temperature. The resulting viscous liquid rested for 5 hours to permit the escape of any air bubbles.

[0066]The polymer solution was casted onto a glass plate into a 250 μm thick film with the use of a doctor knife. The glass plate was then immersed into a non-solvent bath (tap water) at room temperature for at least 12 hours. The membrane was stored in a water bath until use. FIG. 3 depicts a cross-section of the resulting asymmetric membrane.

example 3

Gold Recovery with Microporous PTSC Membrane at Flux=101 L / M2H

[0067]A microporous membrane prepared in accordance with Example 2 was tested with the method(s) described below to assess gold loading of the membrane. The membrane was cut into a four circles, each with an approximate diameter of 2.5 cm and an average dry weight of 14.3 mg. Each membrane was placed on a non-woven polyester circular support of approximately the same size.

[0068]Four aqueous solutions containing gold in 10% HCl were prepared at 100 ppm, 200 ppm, 500 ppm, and 1000 ppm. 10 mL of each solution permeated through a membrane with the use of pressurized air. A difference in pressure of 0.5 bar was sufficient to permeate the solutions through the respective membrane with a flux of 101 L / m2h. FIGS. 4A and 4B depict the membranes before gold absorption (4A) and after gold absorption (4B). Prior to gold absorption, the membrane is an off-white color, and afterward, the membrane is a brownish color. The amount of gold...

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Abstract

The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a national phase application under 35 U.S.C. § 371 of International Application No. PCT / IB2014 / 002354 filed Jul. 3, 2014, which claims the benefit of priority of U.S. Provisional Patent Application No. 61 / 843,091, filed on Jul. 5, 2013. The entire contents of each of the above-referenced disclosures are specifically incorporated herein by reference without disclaimer.BACKGROUND OF THE INVENTION[0002]A. Field of the Invention[0003]The invention generally concerns microporous polymeric membranes for selective recovery of desired metals and methods of making and using the same.[0004]B. Description of Related Art[0005]The demand for precious metals, such as gold, is high and continues to grow. Gold and other precious metals are widely used in electronics, jewelry, catalysts and medical applications. In addition, emerging technologies, such as nanoelectronics and microelectromechanical systems (MEMS), generate more pressure ...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B01D15/00C22B15/00B01D69/02B01D63/00B01D71/66B01D71/62B01D67/00C22B9/02C08J9/26C22B3/00B01D63/08B01D61/14
CPCC22B11/04C22B15/0063B01D63/00C08J9/26C22B9/023B01D67/0016B01D67/0023B01D71/66B01D71/62B01D69/02B01D61/145B01D2325/022B01D2325/12C08J2381/00
Inventor PEINEMANN, KLAUS-VIKTORDE LA PARRA, LUIS FRANCISCO VILLALOBOS VAZQUEZHILKE, ROLAND
Owner KING ABDULLAH UNIV OF SCI & TECH
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